Totaling across summary sheets

edited 12/09/19 in Smartsheet Basics

I have created summary sheets in several of my departmental sheets to take the place of the metric section at the top.  How can I summarize across all of the summary sheets?  I see I can pull them into a report, but I cannot add a Totals or Average field summarize across the summary sheets.  I thought I would simply add a link to my existing metrics rollup sheet but don't seem to be able to do that either.  it possible to link to one of these fields from another sheet?  Or how can I get the totals across multiple summary sheets?